With the rapid development of electronic technologies, liquid crystal display devices become more popular. As known, a drive circuit is used for driving the backlight source of an electronic device such as a liquid crystal display device or a liquid crystal computer.
FIG. 1 is a schematic circuit diagram illustrating the connection between a drive circuit and LED light strips of a conventional liquid crystal display device. As shown in FIG. 1, the LED backlight source of the liquid crystal display device is an LED light strip. The drive circuit for driving the LED light strip comprises an external power supply input terminal U, a boost module 40, a control module N, a rectifier module 20, a filtering module Co, a current sampling module 5, and a light-adjusting module 7.
The boost module 40 is used for receiving the current from the external power supply input terminal U and converting the current into an increased voltage required to power the LED light strip. Then, the increased voltage from the boost module 40 is transmitted to the rectifier module 20.
By the rectifier module 20, the current from the boost module 40 is rectified into a rectified current, and the rectified current is inputted into the filtering module Co and the LED light strips.
The filtering module Co is used for storing the current from the boost module 40 and gradually releasing the current to the LED light strip.
The light-adjusting module 7 is used for receiving a light-adjusting signal and a start signal from an external circuit board (not shown), and transmitting the light-adjusting signal and the start signal to the control module N.
After the start signal is received by the control module N, the control module N enters a working state. In the working state, the magnitude of the current flowing through the LED light strip is sensed by the control module N through the current sampling module 5. According to the light-adjusting signal, the current from the boost module 40 to the rectifier module 20 is adjusted to a desired magnitude by the control module N.
Moreover, the boost module 40 comprises an inductor and a MOS transistor. By controlling the frequency of turning on/off the MOS transistor, the magnitude of the voltage corresponding to the output current of the boost module 40 is controlled by the control module N.
In accordance with the conventional driving method, a boost module 40 is able to drive only one corresponding LED light strip. That is, the drive circuit composed of one boost module 40, one rectifier module 20, one filtering module Co and one current sampling module 5 can be used for driving one LED light strip. For driving two LED light strips, the drive circuit should comprise two boost modules 40, two rectifier modules 20, two filtering modules Co and two current sampling modules 5, and the control module N should be implemented by multiple chips.
From the above discussions, it is found that the conventional drive circuit for driving the LED light strips still has some drawbacks.
For example, if only two LED light strips are installed in an electronic device, the drive circuit for driving these two LED light strips needs two boost modules 40 as shown in FIG. 1. Since the electronic components of the boost module 40 are relatively costly, the electronic device with the drive circuit has higher fabricating cost.